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Figure 5.22 The behaviour of D(q) with binomial multiplicative process.
approximately the same. Therefore, the values q=0, q=3, q=−4 were used in our experiments.
Two kinds of features extracted by applying W and R filters (Equations (5.38) and (5.39)) are used for the purposes of this example. The first is the proportion of the total power spectrum contained in the W filter, i.e. [Wθ1,θ2/ P(u, v)]. Only horizontal and vertical directions within a predefined angular range of 45° (i.e. ±22.5°) were used. The second feature is the proportion of the power spectrum contained in the R filter, i.e. [Rr1,r2/ P(u, v)]. Since both features are sensitive to orientation (i.e. [Wθ1,θ2/P(u,v)]) only, or to frequency (i.e. [Rr1,r2/P(u, v)]) only, it is better to use both filters together to perform texture segmentation. Note that there is no clear rule concerning the choice of a suitable range interval (r1, r2) for the R filter. The range was therefore decided by trial and error methods.
Four texture features, ASM, Con, Ent, and IDM were derived from each subimage for the H, V, LD, RD directions with distance d=1. In order to avoid the angular effect, in which the same texture pattern may spread out in different directions, the feature indices generated for each direction
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